The CDMA (Code Division Multiple Access) 2000 EVDO (Evolution Data Only) is one of conventional standards having been established to achieve high-speed data communications.
The high-speed communication performance of the standard is utilized in providing various services such as moving image distribution and the VOIP (Voice over Internet Protocol) communication. See, e.g., “cdma2000 High Rate Packet Data Air Interface Specification”, 3GPP2 C.50024, 3rd Generation Partnership Project 2, Oct. 27, 2000.
Of these, the VOIP communication takes a form of audio communication where the encoded audio data, which is generated by encoding audio signals, is converted into a series of packets, and then transmitted via a server and a base station.
According to the CDMA2000 EVDO standard, a mobile communication terminal enters into a standby state when no communication is performed for a predetermined time period with the mobile communication terminal.
In the standby state, the mobile communication terminal activates a reception circuit for receiving a report signal at a predetermined cycle (approximately 5.152 seconds) such that it checks intermittently whether an incoming call destined thereto has been received by referring to the report signal, where the predetermined cycle is synchronized with the cycle at which the base station transmits the report signal.
As described above, in the standby state, the mobile communication terminal receives the report signal intermittently. This enables the mobile communication terminal to detect reception of an incoming call destined thereto, while at the same timesaving the battery of the terminal.